Carburetor device



Feb. 12, 1946- H. A. "CARLSON ETAL CARBURETOR DEVICE Filed Nov. 28. 1942 ADJ FIG.4.

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ATTORNEY Patented Feb. 12, 1946 CARBURETOR DEVICE ,Harold A. Carlson, University City, and Olin J. Eickmann, Normandy, Mo., assignors to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application November 28,1942, Serial No. 467,226

Claims. (01. 261-41) This invention relates to carburetors for internal combustion engines and consists in' novel fuel supplying means.

Automotive carburetors, customarily, are provided with main and idling fuel passages or ducts leading from the fuel reservoir to the mixture conduit, respectively, anterior and posterior to the throttle valve which controls the quantity of mixture discharged. A metering orifice is usually provided at or near the inlet endof the main fuel passage and the idling fuel passage usually draws its fuel from the main passage posterior to the metering orifice, this being known as an interconnected fuel system. This type of system has the advantage of providing a and idling port at. the transfer point during the opening movement of the throttle, that is, at the time when fuel starts to emit from the main nozzle. At such time, the superior suction in the main nozzle passage gradually reduces the fuel flow through the idling passage by U-tube action in a. desirable manner. Conversely, when the carburetor is operating with the throttle substantially closed and all fuel is being supplied through the idling passage, the superior suction in this passage tends to draw fuel from the main fuel passage and thus lower the level therein.

This has the undesirable effect of delaying the time when fuel is discharged from the main nozzle as the engine sp ed is increased because of opening of the throttle valve.

The latter condition may be corrected by providing an independent idling system which communicates with the fuelreservoir anteriorto or independently of the main fuel metering orifice. However, with such a fuel system, proper blending of the main and idling discharged at the transfer point is diflicult to accomplish.

Accordingly, it is an object of the present invention to provide a carburetor in which the main and idling fuel systems communicate with the fuel reservoir substantially independently during idling operation, to prevent the lowering of the level in the main fuel passage by U-tube action, while, at the same time, providing for the accurate These objects and other more detailed objects hereafter appearing are attained by the structure illustratedin the accompanying drawing in i which:

. properly blended discharge from the main nozzle horn in, venturis II, and outlet portion l2, flanged,

blending of the main and'idling discharges at the transfer point which is an incident of the interconnected main to idling systems.

A more detailed object is to provide a carburetor having an idling system which operates independently of the main fuel system during idling operation, but which operates as an interconnected idling system thereafter during opening movement of the throttle.

Fig. 1 is a vertical section of a carburetor embodying one form of the invention, the parts be ing spread out diagrammatically in the plan of the view for clearer illustration.

Fig. 2 is a detail view of metering parts of a carburetor in idlingposition, but showing a modification. 1

Fig. 3 is a view of the detail ing the parts in high speed running position.

Fig. 4 is a view similar to Fig. 2 but showing still another modification.

Fig. 5 is a view of the structure in Fig. 4, but

showing the parts in high speed running position instead of in idling position as in Fig. 4.

The structure in Fig. 1 comprises a downdraft mixture barrel or conduit including an air inlet at l3 for attachment in the usual manner to an engin intake manifold (not shown). Air entering the carburetor is controlled by a butterfly choker valve l4 and the quantity of fuel and air mixture discharged is controlled by a throttle valve I5.

A'metering orifice element 25 is provided at the inlet end of passage 22 for limiting the main fuel discharge. This orifice element .is controlled by a metering pin 26 connected at its upper end to a diaphragm 21 mounted on fuel bowl cover 28.

The diaphragm is constantly urged downwardly by a coiled spring 29 and may be moved upwardly against the spring in accordance with suction posterior to the throttle by means of a suction passage 30 communicating with suction chamber 3| above the diaphragm. This metering device is known as a stepup or economizer and functions to enrich the mixture supplied through the main nozzle when the suction posterior to the throttle is relatively low and to reduce the richness of the mixture at relatively high suctions posterior to the throttle. While a suction economizer has been shown, the manual type of economizer in which the metering pin is connected to the throtin Fig. 2. but show- 7 Adjacent the mixture conduit there is provided a fuel reservoir H! in which fuel is tle valve for operation therewith is the equivalent so far as the present invention is concerned since the degree of suction posterior to the throttie, in general, varies inversely with the degree of opening of the throttle valve. Thus, with either the suction or manual type of economizer the main metering orifice will be substantially restricted in the economy range when the throttle is nearly closed and the amount of restrictio will be reduced as the throttle is-opened.

as the throttle-valve is opened piston 61 is moved downwardly to force fuel from cylinder 56 into the mixture conduit through pump outlet passage 43 and accelerating nozzle 44.

The idling system comprises a first vertical passage 48, a cross passage and a second vertical passage extending downwardly along the mix-- ture conduit to idling port.5| adjacent the edge of the throttle valve when closed. Passage .8 communicates with the fuel reservoir through a port 52 and cross passage 49 is provided with a metering restriction 53. Under idling conditions, as will be explained hereafter, the idling system obtains its fuel from the reservoir through port 52 independently of main metering orifice 25, but this system is also interconnected with the main fuel duct by means of a short cross passage 55, valve chamber 51, and an angular passage 58. A disk check valve 58 normally rests upon an annular rib surrounding passage 58 so as to eliminate the interconnection between the main and idling fuel systems. The travel of disk check ascents the main and idling disportion 66 of the orifice member.

During idling operation, the enlarged lower extremity of. metering pin 26a substantially fills restriction 65, but ample space is provided in the countersunk portion 61 of the orifice member around the pin to supply fuel for idling, this fuel being limited by metering tube 66 in passage 48a. As the throttle valve is opened, to initiate the discharge from the main nozzle, metering pin 26a is lowered so as to open restriction 66 (Fig. 3) permitting the drawing of adequate quantities of fuel through main nozzle passages or ducts 22a, 23a. Thereafter, idling port 52a will be exposed to the flow of fuel through countersunk portion 61 in the orifice member, the effect being that the effective suction in and, consequently, the discharge from the idling system willbe reduced as the flow through the main fuel system is increased. The consequent blending of the discharges from the idling and main nozzles is an important advantage of the so-called interconnected idle.

In Figs. 4 and 5, metering orifice member 25b is shaped, as in Fig. l, but is controlled by a metering pin 26b carrying an extension pin 10. Idling passagelllb connects with cross passage 22b of the main fuel system posterior to orifice member 25b. However, passage 22b additionally is controlled by a plug lodged in the valve I chamber.

The-main and idling fuel supply systems operate as follows: 7

When the carburetor is operating with th throttle valve closed, as in Fig. 1, substantially no suction will be applied to main nozzle 26, valve 59 will be seated, and all of the fuel will be supplied through idling port 5|, a portion of which opens into the mixture conduit posterior to throttle i5. The idling suction will be transmitted through passages 50, 49, and 48 to port 52 opening into the fuel reservoir. A portion of this suction will also be transmitted through angular passage 58 so as to draw check 59 against its seat and thus close off the communication between the idling system and main fuel passage 23. Consequently, all fuel for idling will be supplied from the reservoir through port 52 and independently of main metering orifice 25. As the throttle valve is opened, to increase the. speed of the engine, suction will be applied, to main nozzle 24 to draw fuel therefrom; Prior to such emission of fuel through the main nozzle, the fuel in main nozzle passage 23 will stand at the constant level :r:c since the operation of the idling system does not materially effect this level. However, as the suction in the main nozzle passages exceeds that in the idling system. disk 59 will be lifted so that the main nozzle suction will be applied to the idling system and the idling discharge will be gradually reduced as the discharge to the main nozzle is increased. This U-tube action, in which the interconnected main and idling passages form the legs o f. -,they, provides for the desirable communicates with the fuel reservoir through a diagonal duct 52b which is independent of orifice member 25b. Slidable on pin 10 is a valve II which cooperates with a valve seat 12 threaded into the bottom of the fuel reservoir.

This form operates as follows:

During idling, the lower extremity of metering pin 26b substantially restricts orifice member 25b and valve H is lifted from its seat 12 (Fig. 4) to permit the drawing of idling fuelthrough independent diagonal passage 52b. As the throttle valve is opened to speed the engine, metering pin 26b is lowered, as indicated in Fig. 5, to increase the effective opening in orifice member 25b and valve ll moves against seat 12 to cut off communication between cross passage 22b and diagonal duct 52b. Thereafter, suction in the main f-uel passages 22b and 23b is applied to main fuel orifice 25b, to draw fuel therethrough,- and also to idling passage 48b so as to reduce the idling discharge, as in the previous form.

The structure above described combines the advantages of independent and interconnected main and idling fuel systems and, at the same time, eliminates the disadvantages of both. The arrangements shown are simple and effective, but may be modified in various respects as will occur to those skilled in the art. The exclusive use of .all modifications as come within the scope of the appended claims is contemplated.

We claim: v

1. In a carburetor, a mixture conduit a throttle, a fuel reservoir, main and idling fuel ducts for supplying fuel from said reservoir to I said conduit, respectively, anterior and posterior having reservoir through a metering restriction independent of said orifice, a fuel passage between said ducts for connecting the same, and a check valve for said passage movable to closed position responsive to the existence of greater suction in said idling duct than in said main duct to prevent the drawing of fuel during idling from said main passage.

2. In a carburetor, a mixture conduit having a throttle. a fuel reservoir, a mainfuel duct communicating with said reservoir through a metering restriction spaced inwardly from the mouth of said duct, an idling fuel duct communicating with said main duct immediately anterior to said restriction, a metering pin controlling said restriction, and means for actuating said pin to I during idling, and an idling fuel duct connecting I with said orifice immediately anterior to said portion whereby said idling passage is disconnected from said main duct during idlingand, upon opening of said economizer valve, fuel will be drawn from said idling duct as well as said reservoir into said main duct.

4. In a carburetor, a mixture conduit, a throttle therein, a constant level fuel reservoir, idling and main fuel passages discharging into said conduit, means connecting said passages to said reservoir, a fuel duct between said passages,- and a valve controlling said fuel duct, said valve being constructed and arranged to be substantially closed by manifold suction during idling and to be opened when the carburetor is operating with the throttle substantially opened.

5. In a carburetor for an internal combustion engine, a mixture conduit having a throttle, a

fuel reservoir, a main fuel duct for supplying fuel from said reservoir to said conduit, a two-step metering orifice in said duct, an idling fuel duct having a constantly open connection with said reservoir through the anterior step of said orifice, and an economizer valve adapted to substantially close the posterior step of said orifice during idling operation and to maintain the same open during higher speed operation of th associated engine whereby, at such time, suction conditions in said main duct reduce the flow in said idling duct.

HAROLD A; CARLSON. OLIN J. EICKMANN. 

